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Old Apr 26, 2006, 9:04 AM   #1
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Hey folks great site here and very encouraging community. Good to see.

Anyway I'm an amatuer photographer, furniture designer by profession

I'm well used to filmSLR's but have decided to make the leap to digital and have pretty much decided on the olympus SP-350. I've decided a digital SLR is economicaly unviable considering my level of dedication. I live a busy life.

I knowa little aboutdigital photography, i know normal 35mm film is equivalent to about 20MP.

SO, what i would like to know is what size can the SP-350's 8MP photos be printed at witout loosing qualitiy and what size can they be printed at where the quality is lost but still acceptable.

Your input will be greatly apppreciated.

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Old Apr 26, 2006, 11:10 AM   #2
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The best tests comparing film and digital that I have encountered kept the film completely in the chemical process and compared prints. Their conclusion was that the best ASA100 consumer color film was about equal to 6Mp. Professional slide film like Provia gave the equivalent of about 11Mp. Those megapixel ratings were from DSLR cameras with quality lenses.

Film gives better dynamic range and consumer film gives a much larger exposure latitude. The tests were just for resolution. I have seen other tests that converted film and slides to digital on professional scanners that came up with even lower Mp numbers for film. But I think a fair comparison keeps film completely in the chemical/optical process all the way to the print.

Resolution tests on cameras with small sensors like the SP350 show resolution generally equivalent to DSLRs. Where they aren't as good is in dynamic range and noise. If you are familiar with 35mm printing I think you would find that images from the 8Mp Oly would print to around the same size as with good consumer ASA100 film.

Some people have magic numbers like 300 PPI below which you start losing quality. I've run tests on a couple of photo printers and can't see improvement over 250 PPI even under a loupe. The point of diminishing returns for me is around 180 PPI. You have to inspect the image up very close to see improvement over 180 PPI. Those numbers might be different for professional processing, but I wouldn't think by much. You can get photos that look great on the wall at much lower resolutions, although you should smooth them out with an upsample. The larger the photo the greater the viewing distance under most circumstances.

Subject matter makes a difference. I think the thing that requires the highest resolution is a large group shot. People look very closely to see the individual faces and a drop off in resolution is very apparent. Portraits can usually do well with lower resolution where things with detail that people might look at more closely don't.

I've read posts by people who had 2Mp images printed at 16 X 20 and hung them on their office wall. They said people were surprised it wasn't a film photo, but I would guess it was in a place where the viewer couldn't get too close. I wouldn't be happy with that resolution and would probably print the image smaller. But every display situation and subject is different.

Your ability at post processing also makes a difference. Upsamples are often grossly overrated, but good sharpening, saturation and contrast improvements can make a photo look better.

The best 16 X 20 crop you can get from the SP350 is around 153 PPI. With an upsample and good post processing a print from 150 PPI can look quite good for most subjects.

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Old Apr 26, 2006, 3:04 PM   #3
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Better non-SLR digicams are quite versatile so they're definitely very viable option for dSLR if there's no need for lower light moving target photos.

So what kind targets you would photograph, is it general photography with landscapes, architecture or would it be more wild animals/birds?
In first case I would suggest camera with good wide angle, also image stabilization would be good for lower light stationary targets. (that Oly lacks IS)
Also do you have size limit? Should it fit to pocket or would smaller than SLR be enough.

SP350 seems to be extreme power hog... (if this would have been Minolta camera people would have lynched it)
Battery life was also disappointing. At first I thought that the set of 2500mAh NiMH cells that I was using were bad. However it seemed no matter what set was used, it was about the same. Olympus does not specify how many images can be captured, but I found it took nearly three battery changes to capture about 100 shots and conclude several of our other tests
No wonder they won't specify battery life.

As for how is printability of non-dSLR pictures at higher ISO/sensitivity shots here's some data in comparison of KonicaMinolta A2 and Canon 20D dSLR.
ISO 100: The noise was virtually indistinguishable even when viewing at 25"x19" in size.
ISO 200: Noise is detectable in smooth areas at 25" wide but not at 16" wide on the A2. No noise can be seen at ISO 200 on the 20D.
ISO 400: The difference here is very apparent. The A2 shows clearly visible noise at 25" wide. At 16" the noise is barely detectable. At 12" and below, noise cannot be seen. No noise can be found on the 20D up to 25" wide.
ISO 800: Noise is now visible at 16" wide and above and disturbing at 25" wide for the A2. No noise to be found on the 20D up to 25" wide.
Visible noise levels at various print size show that the A2 is perfectly suited at ISO 200 (or less) up to 25" wide and at ISO 800 up to 12" wide.
But pixel density of that camera's sensor is ~140 000 pixels/sqmm versus ~210 000 pixels/sqmm of this smaller sensor Oly, also that 16" would be more practical for closer inspection prints, at 25" size would be for "poster inspection distance".
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Old May 1, 2006, 12:19 PM   #4
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I agree with what others have stated. For Higher ISO settings using a good Noise Reduction program will help greatly when used in moderation.

PPI should be determined on an image to image basis, not a rule of 300 or 180 or 240. Instead do some trial and error and see what is acceptable for the image that will be printed and the viewing distance.

Regarding the oly you are intested in here are the print sizes it will produce at various PPI (used the calculator at http://www.mattspinelli.com/ppicalc.html ):
(Assuming 8.0 megapixels exactly with a 4:3 aspect ratio)

4 x 6 = 544.17
5 x 7 = 466.43
6 x 8 = 408.13
6 x 9 = 362.78
8 x 10 = 306.13
8 x 12 = 272.08
8.5 x 11 = 288.12
10 x 13 = 244.9
10 x 15 = 217.67
11 x 14 = 222.64
12 x 16 = 204.06
12 x 18 = 181.39
13 x 19 = 171.84
16 x 20 = 153.06
16 x 24 = 136.04
18 x 24 = 136.04
20 x 30 = 108.83
24 x 36 = 90.69
30 x 40 = 81.63

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Old May 1, 2006, 7:03 PM   #5
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What you are going to do with the print, and the amount of detail, will determine the largest size more than ppi - and thus pixel count. Billboards look clear fromtheir designed viewing distance and they are printed at something like 10ppi. A 40x50" print made from an 8x10" negative isn't likely to stand up to someone asking, "Is that a squirel or a bird in the 37th tree from the left?", as they pull a loupe out of their pocket.

Try some prints and find out for yourself. To keep the price of printing down, crop out a small section with the most detail and print it at 4x6".
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